The legislation will affect mega-retailers with 1,000 or more warehouse workers.

A new law will pry open the black box of how Amazon monitors, rewards, and disciplines its fulfillment center employees.

On Wednesday, California Gov. Gavin Newsom signed a bill into law that directly affects "mega-retailers" like Amazon, and how these companies use algorithms to manage warehouse workers. Mega-retailers are those that employ more than 1,000 warehouse workers, and they include one of Amazon's main competitors, Walmart.

The bill, AB 701, takes effect on Jan. 1 and gives companies 30 days to disclose in writing "each quota to which the employee is subject."

Traditional quotas let workers know what’s expected of them. But workers and government regulators can’t see what goes into the algorithms used by Amazon and other companies to judge productivity. So an employee could be penalized for taking too many bathroom breaks and never know that’s why their hours were cut or they were fired.

Under the new law, companies will have to detail "the quantified number of tasks to be performed, or materials to be produced or handled, within the defined time period, and any potential adverse employment action that could result from failure to meet the quota."

A recent report from the anti-trust advocacy group Open Markets Institute details how Amazon surveils its workers.

Amazon says this technology — including cameras in delivery vans that are always on, and an app that monitors driving — are meant to promote safety. But worker advocates say they have resulted in unfair firings, and put stress on an already harried workforce.

Amazon employs 150,000 people in California, according to the Associated Press. The new law won’t affect the company’s delivery drivers, just its warehouse workers.

Reports claim Amazon workers have skipped trips to the bathroom to meet productivity goals. The bill prohibits retaliating against workers who fail to meet quotas because they're taking breaks or using the restroom.

Workers are also now entitled to see 90 days worth of their own data, and have the power to sue if they've been disciplined for not keeping up with burdensome quotas, or if they believe their quotas violate labor laws mandating worker protections, like bathroom breaks.

Amazon did not issue a statement regarding the bill's passage, nor did it respond to Mashable's request for comment. In the past, it has pushed back on the idea that its workers struggle under the pressure of constant surveillance and a frenzied work pace.

It recently implemented an expensive "wellness program." Now it looks like California workers will get what they actually need — bathroom breaks and the power to fight back.